OBJECTIVE: Evaluate the neurodevelopmental outcome (NDO) of patients with hypoplastic left heart synbdrome (HLHS) following surgical palliation. APPROACH: 1) Perform neurodevelopmental testing on HLHS patients; 2) Compare NDO of HLHS patients to NDO of healthy children and to NDO of patients with non-HLHS congenital heart lesions requiring a similar surgical approach; 3) Evaluate factors in these patients which may contribute to abnormal neurodevelopment including structural abnormalities of the central nervous system and perioperative stresses. SIGNIFICANCE: May impact future approach to treating patients with HLHS.